'This massive collection is one of the most important we have received in the last 70 years,' says Douglas Russell, the Museum's Senior Curator of Birds' Eggs and Nests.

'Importantly, this collection is extremely well-documented, containing data on where and when each egg was collected. This level of detail is vital if we want to use such collections for scientific research.'

Photograph of Gerald Tomkinson with an Egyptian vulture (Neophron percnopterus) nest, 8 May 1919 at Casas Viejas in Spain. Tomkinson described the nest as 'a huge structure about 4 foot [1.2 metres] across'.

A lifetime of egg collecting

Gerald Tomkinson (1876-1959) started collecting eggs as a teenager and continued doing so regularly until the 1950s. His collection includes 325 European species and subspecies, including nearly all those known to breed or to have bred in Britain.

The collection is highly detailed, with information on the provenance of each egg.

'The collection is also the only one we have received with such a detailed series of photograph albums showing his collecting over the years,' says Russell.

The collection contains around 5,000 clutches of eggs, sometimes with additional items found in the nests. For example, in 1937 Tomkinson collected a clutch of peregrine falcon eggs from Cwmdu in the Black Mountains in Wales. In the nest he found the leftover remains of birds that the peregrines had feasted on - the leg rings from 15 racing pigeon and the skull and beak of a common snipe.

His collection was donated by his son to the Wildfowl & Wetlands Trust in the 1970s.

Peregrine falcon eggs collected by Tomkinson from Brecon in Wales on 18 April 1937, with the 15 racing pigeon rings and snipe skull also found in the nest

Using collections for ecological research

The Museum at Tring houses over 200,000 clutches of eggs in its collection - in total more than a million individual eggs.

Data-rich historical collections such as this are especially important to science as a source of information on the lives and past distributions of bird populations.

Scientists can use these collections to study the timing of the seasonal laying of eggs and whether this is affected by climate change and other factors.

They can also check whether a species' range has changed by examining where the nests were found.

A celebrated example of using egg collections in research was when British scientist Derek Ratcliffe began investigating the dramatic fall in peregrine falcon populations after the Second World War. Ratcliffe confirmed that this was due to the introduction of the pesticide DDT, which was being sprayed on farmland and entering the food chain.

By examining peregrine eggs collected before and after the war, researchers could see that the DDT had caused the eggs to become thinner, making them more likely to break under the weight of their incubating parents.

Eurasian golden plover (Pluvialis apricaria) eggs collected by Tomkinson near Krampanes, Lapland on 8 June 1935. These specimens are potentially useful for investigating whether warmer springs are leading to earlier breeding of golden plovers.

Researchers flock to egg acquisition

A number of scientists have already asked to come and carry out research on the eggs from the Tomkinson Collection, says Russell.

'Professor Tim Birkhead from the University of Sheffield is planning to work with a series of around 40 Brünnich's guillemot eggs from Spitsbergen [in Norway]. Norwegian researchers will also be coming this summer to look at the cuckoo eggs.'

Museum Senior Curator Douglas Russell with a tray of tree pipit (Anthus trivialis) eggs from the Tomkinson Collection. The associated labels document where and when they were collected.